Switch for knitting machine stop mechanism



July 3, 1956 D. PERNICK ET AL 2,752,767

SWITCH FOR KNITTING MACHINE STOP MECHANISM Filed June 7, 1954 gm i h H SWITCH FOR KNITTING MACHINE STOP MECHANISM David Pei-nick, Brooklyn, and Frederick L. Aibel, Ossining, N. Y.

Application June 7, 1954, Serial No. 434,725

16 Claims. (Cl. 66-163) The present invention relates to knitting machines of the flat bed type, such as Tricot and Raschel machines and the like, having thread guides for moving the threads about the needles to form loops and, more particularly, to knock-off or stop mechanisms for such machines.

One of the problems in the knitting of fabric is the Waste occasioned by defects in the fabric. This is particularly serious in connection with knitting machines of the Tricot type which have a very wide bed and are operated at high speeds, because one improperly formed stitch in a course or several courses renders a wide piece of fabric defective. In the event one or more of the warp threads supplied to the knitting elements of the machine should break because of excessive tension, which frequently occurs at high speed operation, a considerable length of fabric having imperfections therein may be knitted before the operator detects the same and can stop the machine.

Accordingly, an object of the present invention is to provide means for automatically detecting individual thread breakage of the warp threads supplied to the knitting elements and immediately stopping the knitting machine.

Another object is to provide such means which can be incorporated in newly built machines and can also be installed on existing machines by utilizing modified thread guides and a contact element on the guide bar.

A further object is to accomplish the foregoing in a simple, practical and economical manner.

Other and further features and objects of the invention will become apparent during the description in the following specification in conjunction with the accompanying drawing.

In the drawing:

Fig. 1 is a fragmentary front elevational view of a guide bar and the thread guides thereof, embodying the present invention.

Fig. 2 is a side view taken substantially along the line 22 on Fig. 1.

Fig. 3 is a sectional view taken along the line 33 on Fig. 2.

Fig. 4 is a view similar to Fig. 1 illustrating another embodiment of the present invention.

Fig. 5 is a side view taken substantially along the line 55 on Fig. 4.

Fig. 6 is a perspective view of one of the switch levers shown in Figs. 4 and 5.

Referring to the drawing in detail and, more particularly to Figs. 1 to 3 thereof, the thread guide section of a straight knitting machine of the Raschel or Tricot type, for example, is shown which essentially comprises a guide bar 19, a switch contact element 11 adjacent the guide bar and electrically insulated therefrom, thread guides 12 carried by the bar 10, and pivotally mounted levers 13 associated with the guides having a portion adapted to contact the element 11 upon breakage of the thread T passing through the guides, the levers normally being nited States Patent 0 prevented from permitting the portion to contact the element by the thread.

In this embodiment of the invention the element 11 is a strip of electrically conductive material which is carried by the bar 10 and extends lengthwise thereof, and the guides 12 each have an offset portion 14 adjacent the thread guiding eye thereof; and a rod 15 extends through the guides adjacent the end supported by the bar.

Each of the levers 13 is pivotally mounted on the rod between adjacent pairs of thread guides 12 and is in electrical connection therewith. The lever comprises an upper arm 16 having a portion 17 at the end thereof for engaging the element 11; and a lower arm 18 having a lateral portion 19 formed with an open eye or recess 20 through which the thread passes before it passes through the eye of a guide 12 adjacent the lever, and having an extension 21 between the rod 15 and the lateral portion 19 for engaging a guide 12 adjacent the lever to limit the extent of movement of the lever.

In operation, the thread T passing through the eye 20 of the lever urges the lever in a clockwise direction, as shown in Fig. 2, and holds the extension 21 against the guide 12, whereby the portion 17 is held out of contact with the element 11. However, should the thread T be broken, the lever 13 is released and oscillation of the guide bar It) will cause the lever 13 to rock, whereby the portion 17 contacts the element 11 to close a circuit (not shown) for effecting stoppage of the knitting machine.

In Figs. 4 to 6, another embodiment of the invention is shown, wherein the guide bar 10 has a switch contact element 11a mounted thereon and spaced therefrom by supporting members 23 secured to the guide bar, and has a plurality of thread guides 12a thereon. The guides, in this embodiment, each has a longitudinal slot or recess 24 in one edge thereof, and a lever 13a is pivotally mounted in each slot at the lower end thereof by a pin 25 and has an extension 21a at the upper end thereof disposed between adjacent guides to limit the extent of movement thereof.

In operation, when the thread T is normally tensioned and passes through the eye of the guide, the extension 21a either contacts the guide or is prevented from contacting the element He: by the thread which is substantially in vertical alignment therewith. However, should the thread T be broken, oscillation of the guide bar 10 will cause the extension 21a to contact the element 11a because the thread no longer restrains the same, whereby a circuit (not shown) is closed for effecting stoppage of the knitting machine.

From the foregoing description, it will be seen that the present invention provides a novel and effective arrangement for stopping the operation of a knitting machine in response to breakage of any other thread supplied to the knitting elements thereof.

It is understood that various changes may be made in the construction of the device of this invention without departing from the principle thereof.

What is claimed is:

1. In a warp knitting machine, the combination of an oscillating guide bar, a switch contact element adjacent said guide bar and electrically insulated therefrom, a thread guide carried by said bar, and a pivotally mounted lever associated with said guide having a portion adapted to contact said element upon breakage of a thread passing through said thread guide, said lever normally being prevented by the thread from permitting said portion to contact said element.

2. A knitting machine according to claim 1, wherein said element is supported by said guide bar.

3. A knitting machine according to claim 1, wherein said lever is pivotally mounted on said guide.

4. A knitting machine according to claim 3, wherein said guide has a slot therein in which said lever is pivotally mounted.

5. A knitting machine according to claim 4, wherein said portion extends laterally with respect to said lever and is normally prevented from contacting said element by the thread.

6. A knitting machine according to claim 1, wherein a plurality of thread guides are carried by said bar and each guide has one of said levers associated therewith, and said element extends lengthwise with respect to said bar.

7. A knitting machine according to claim 1, wherein said lever has a first arm provided with said portion and has a second arm adapted to be engaged by the thread to normally prevent said portion from contacting said element.

8. A knitting machine according to claim 7, wherein said second arm has an open eye through which the thread passes.

9. A knitting machine according to claim 8, wherein said second arm has an extension adapted to limit the extent of movement thereof.

10. A knitting machine according to claim 8, wherein said second arm has a lateral portion provided with said open eye.

11. A knitting machine according to claim 10, wherein said thread guide has an offset portion adjacent said lateral portion.

12. A knitting machine according to claim 7, wherein a plurality of thread guides are carried by said bar and a lever is pivotally mounted between each pair of adjacent guides.

13. A knitting machine according to claim 12, wherein said switch contact element is extended lengthwise with respect to said bar and is mounted thereon out of electrical contact therewith and each of said levers is adapted to contact said element with said portion on the first arm thereof.

14. A knitting machine according to claim 13, wherein a rod extends through said guides and said levers are pivotally mounted thereon.

15. A knitting machine according to claim 14, wherein said rod is in electrical connection with said levers.

16. In a warp knitting machine, the combination of an oscillating guide bar, a switch contact element adjacent said guide bar and out of electrical connection therewith,

an apertured thread guide carried by said guide bar through which a thread is adapted to pass and be maintained thereby in a predetermined path, and a movably mounted member adjacent said thread guide constructed and arranged for oscillation with said guide bar and said thread guide and for movement in a path to engage said contact element, said member having a portion which is engaged by the thread while maintained in its predetermined path to restrain said member against movement into engagement with said contact element and which when released upon failure of the thread being maintained in its predetermined path causes said member to be influenced by the oscillation thereof to move into engagement with said contact element.

References Cited in the file of this patent UNITED STATES PATENTS 1,942,524 Welchet al. Jan. 9, 1934 

